Calibration apparatus for a medical tool

Abstract

A calibration apparatus is provided for calibrating a medical tool having a tool tracking marker. The medical tool and the calibration apparatus are for use with a medical navigation system. The calibration apparatus comprises a frame, a frame tracking marker attached to the frame, and a reference point formed on the frame. The reference point provides a known spatial reference point relative to the frame tracking marker.

We claim: 
     
         1 . A calibration apparatus for calibrating a medical tool having a tool tracking marker, the medical tool and the calibration apparatus for use with a medical navigation system, the calibration apparatus comprising:
 a frame;   a frame tracking marker attached to the frame; and   a reference point formed on the frame, the reference point providing a known spatial reference point relative to the frame tracking marker.   
     
     
         2 . The calibration apparatus according to  claim 1 , wherein the frame tracking marker includes at least one of a passive reflective tracking sphere, an active infrared (IR) marker, an active light emitting diode (LED), and a graphical pattern. 
     
     
         3 . The calibration apparatus according to  claim 2 , wherein the frame has at least three tracking markers attached to a same side of the frame. 
     
     
         4 . The calibration apparatus according to  claim 3 , wherein the reference point includes a divot and the medical tool has at least three tracking markers attached thereto and a tip of the medical tool is insertable into the divot to abut against a floor of the divot for validation of the medical tool dimensions by the medical navigation system. 
     
     
         5 . The calibration apparatus according to  claim 4 , wherein the frame and the medical tool each have at least four tracking markers attached thereto and a deformed medical tool is re-registerable with the medical navigation system such that the medical navigation system learns the new dimensions of the deformed tool. 
     
     
         6 . The calibration apparatus according to  claim 1 , wherein the apparatus has a front side, a back side, a right side, a left side, a top side, and a bottom side, and the apparatus has at least three frame tracking markers attached to a same side of the apparatus. 
     
     
         7 . The calibration apparatus according to  claim 6 , wherein the calibration apparatus exists in three dimensional space having an X-axis, a Y-axis, and a Z-axis, and at least one of the at least three frame tracking markers differs in position in the X direction from the remaining tracking makers, at least one of the at least three frame tracking markers differs in position in the Y direction from the remaining tracking makers, and at least one of the at least three frame tracking markers differs in position in the Z direction from the remaining tracking makers. 
     
     
         8 . The calibration apparatus according to  claim 6 , wherein the apparatus includes a cavity between the right side and the left side of the frame and between the top side and the bottom side of the frame, the cavity having a top side, a bottom side, a right side, and a left side, the reference point being positioned on the bottom side of the cavity. 
     
     
         9 . The calibration apparatus according to  claim 8 , further including a retaining orifice positioned on a top side of the frame and extending through to the top side of the cavity, the retaining orifice for receiving the medical tool as the tip of the medical tool is positioned in the reference point, the retaining orifice holding the medical tool in an upright position when the tip of the medical tool rests in the reference point. 
     
     
         10 . The calibration apparatus according to  claim 4 , further including a second reference point formed on the frame for further validating the medical tool dimensions by the medical navigation system. 
     
     
         11 . A medical navigation system, comprising:
 a medical tool having a tool tracking marker;   a calibration apparatus for calibrating the medical tool, the calibration apparatus having:
 a frame; 
 a frame tracking marker attached to the frame; and 
 a reference point formed on the frame, the reference point providing a known spatial reference point relative to the frame tracking marker; and 
   a controller having a sensor for detecting the tracking makers, the sensor providing a signal to the controller indicating positions of the tracking markers in space.   
     
     
         12 . The medical navigation system according to  claim 11 , wherein the frame tracking marker and the tool tracking marker include at least one of a passive reflective tracking sphere, an active infrared (IR) marker, an active light emitting diode (LED), and a graphical pattern. 
     
     
         13 . The medical navigation system according to  claim 12 , wherein the reference point includes a divot, the frame has at least three tracking markers attached to a same side of the frame and the medical tool has at least three tracking markers attached thereto and a tip of the medical tool is insertable into the divot to abut against a floor of the divot for validation of the medical tool dimensions by the medical navigation system based on signals provided by the sensor. 
     
     
         14 . The medical navigation system according to  claim 13 , wherein the frame and the medical tool each have at least four tracking markers attached thereto and a deformed medical tool is re-registerable with the medical navigation system such that the medical navigation system learns the new dimensions of the deformed tool. 
     
     
         15 . The medical navigation system according to  claim 11 , wherein the calibration apparatus has a front side, a back side, a right side, a left side, a top side, and a bottom side, and the apparatus has at least three frame tracking markers attached to a same side of the apparatus, wherein the calibration apparatus exists in three dimensional space having an X-axis, a Y-axis, and a Z-axis, and at least one of the at least three frame tracking markers differs in position in the X direction from the remaining frame tracking makers, at least one of the at least three frame tracking markers differs in position in the Y direction from the remaining frame tracking makers, and at least one of the at least three frame tracking markers differs in position in the Z direction from the remaining frame tracking makers. 
     
     
         16 . The medical navigation system according to  claim 15 , wherein the calibration apparatus includes a cavity between the right side and the left side of the frame and between the top side and the bottom side of the frame, the cavity having a top side, a bottom side, a right side, and a left side, the reference point being positioned on the bottom side of the cavity. 
     
     
         17 . The medical navigation system according to  claim 16 , further including a retaining orifice positioned on a top side of the frame and extending through to the top side of the cavity, the retaining orifice for receiving the medical tool as the tip of the medical tool is positioned in the reference point, the retaining orifice holding the medical tool in an upright position when the tip of the medical tool rests in the reference point. 
     
     
         18 . The medical navigation system according to  claim 11 , wherein the reference point includes a divot, the calibration apparatus further including a second divot formed on the frame for further validating the medical tool dimensions by the medical navigation system. 
     
     
         19 . A method of verifying dimensions of a medical tool having an attached tool tracking maker using a calibration apparatus having a frame, a frame tracking marker attached to the frame and a reference point formed on the frame, the reference point providing a known spatial reference point relative to the frame tracking marker, the method comprising:
 detecting the tool tracking maker and the frame tracking maker;   calculating the expected spatial relationship of the tool tracking maker relative to the frame tracking maker; and   reregistering the tool when the dimensions of the medical tool have changed beyond a threshold.